The present invention relates to a method for computing a target setting value—which is adapted to a harvesting process—for a control parameter of a working unit of a harvesting machine, in particular a combine harvester. The present invention further relates to a method and a corresponding control unit for controlling a working unit of a harvesting machine, and a harvesting machine with a control unit of this type.
Modern agricultural harvesting machines, in particular self-propelled harvesting machines such as combine harvesters, forage harvesters, etc., include one or more adjustable working units for processing various types of crops. With modern harvesting machines, the individual units are equipped with adjusting devices—which are usually remotely controllable from the driver's cab—with which various control parameters of the working units can be set. Typical working units of a combine harvester are, e.g., the threshing mechanism, which usually includes a concave and one or more cylinders, and a cleaning unit located downstream of the threshing mechanism, the cleaning unit typically including a blower and a plurality of sieves. Different types of crops and harvesting conditions, such as moisture, crop height, ground conditions, etc., require that the individual units and/or their adjustable control parameters be adjusted as exactly as possible to the specific, on-going harvesting process, in order to obtain an optimum operating result overall.
Despite the many setting aids offered to operators by the manufacturers of harvesting machines—such as comprehensive operator training, printed lists of setting values predetermined for various harvesting situations that the operator can refer to, and electronic tools such as electronic fieldwork information systems preprogrammed with optimized combinations of setting values for highly diverse harvesting situations for the operator to choose from—it is still relatively difficult for operators to adjust the machine such that it functions in an optimum manner in accordance with the desired requirements. This is the case, in particular, for inexperienced and/or untrained operators, particularly at the beginning of a harvesting season. In many cases, therefore, the harvesting machine and/or its working units are not adapted to the current harvesting process in an optimum manner. As a result, the available harvesting capacity of the machine is under-utilized, poor operating results are obtained, or, in some cases, unnecessary crop losses result.
To solve this problem, DE 101 47 733 A1 provides an automated method for computing a setting for an agricultural harvesting machine which has been adapted to the harvesting process. With this method, one control parameter of the harvesting machine is varied while the setting remains the same and the harvesting conditions are the same. The operating results are subsequently compared to select exactly that setting value for the particular control parameter that delivered a better operating result. Using this method, even inexperienced operators learn relatively quickly whether, when and to what extent the varied control parameter affects the operating result, and they can set the control parameter accordingly. The setting can also be carried out automatically, of course. The operating-result values can be recorded, in particular, and, by referring to the recorded operating results, a relationship between the varied setting parameter and the operating result obtained can be identified. Based on this relationship, an optimum setting parameter that leads to the best operating result can then be selected.
Since a system is involved with most of the working units on harvesting machines, however, setting one control parameter affects highly diverse operating-result parameters. For example, setting a blower speed—which is a single control parameter of the cleaning unit of a combine harvester—influences not only the losses due to cleaning, but also the total tailings and grain tailings. The tailings are the crop material components that are returned to the threshing unit to be threshed again. A distinction is made between total tailings, which is the total quantity of tailings, and grain tailings, which refers to the grain portion of the total tailings. The losses due to cleaning are the portions of grain carried out of the machine with the non-grain components as a loss. A main objective of selecting the setting, of course, is to keep losses to a minimum. Since tailings place an additional load on the threshing unit, however, the quantity of tailings should also be a minimum, in the ideal case. Unfortunately, it is not necessarily the case that, when the blower speed is varied from a certain point outward in a certain direction, that all of the various operating-result parameters mentioned above, e.g., losses due to cleaning, total tailings and grain tailings, are automatically improved, since the minimum values of the various operating-result parameters are not all located at the same blower speed. This example also applies for other control parameters of the cleaning unit, e.g., the upper sieve width setting and the lower sieve width setting, and for a large number of other working units and their control parameters. In most cases, the various operating-result parameters are a not a function of just one control parameter, but of a large number of control parameters. Conversely, changing one control parameter affects a plurality of operating-result parameters.